Indium is used as sputtering target for forming photoabsorption layer of Cu—In—Ga—Se system (CIGS system) thin-film solar cell.
Traditionally, as disclosed in Patent document 1, indium target is produced by attaching indium and the like, on a backing plate, and next, setting a mold on the backing plate, and then pouring indium into the mold and casting them.    (Patent documents 1) Japanese Examined Patent Publication No. 63-44820